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Hettiarachchi A, Cnockaert M, Joossens M, Gekière A, Meeus I, Vereecken NJ, Michez D, Smagghe G, Vandamme P. The wild solitary bees Andrena vaga, Anthophora plumipes, Colletes cunicularius, and Osmia cornuta microbiota are host specific and dominated by endosymbionts and environmental microorganisms. MICROBIAL ECOLOGY 2023; 86:3013-3026. [PMID: 37794084 DOI: 10.1007/s00248-023-02304-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 09/19/2023] [Indexed: 10/06/2023]
Abstract
We characterized the microbial communities of the crop, midgut, hindgut, and ovaries of the wild solitary bees Andrena vaga, Anthophora plumipes, Colletes cunicularius, and Osmia cornuta through 16S rRNA gene and ITS2 amplicon sequencing and a large-scale isolation campaign. The bacterial communities of these bees were dominated by endosymbionts of the genera Wolbachia and Spiroplasma. Bacterial and yeast genera representing the remaining predominant taxa were linked to an environmental origin. While only a single sampling site was examined for Andrena vaga, Anthophora plumipes, and Colletes cunicularius, and two sampling sites for Osmia cornuta, the microbiota appeared to be host specific: bacterial, but not fungal, communities generally differed between the analyzed bee species, gut compartments and ovaries. This may suggest a selective process determined by floral and host traits. Many of the gut symbionts identified in the present study are characterized by metabolic versatility. Whether they exert similar functionalities within the bee gut and thus functional redundancy remains to be elucidated.
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Affiliation(s)
- Amanda Hettiarachchi
- Laboratory of Microbiology, Department of Biochemistry and Microbiology, Faculty of Sciences, Ghent University, K.L. Ledeganckstraat 35, 9000, Ghent, Belgium
| | - Margo Cnockaert
- Laboratory of Microbiology, Department of Biochemistry and Microbiology, Faculty of Sciences, Ghent University, K.L. Ledeganckstraat 35, 9000, Ghent, Belgium
| | - Marie Joossens
- Laboratory of Microbiology, Department of Biochemistry and Microbiology, Faculty of Sciences, Ghent University, K.L. Ledeganckstraat 35, 9000, Ghent, Belgium
| | - Antoine Gekière
- Laboratory of Zoology, Research Institute for Biosciences, University of Mons, Place du parc 20, 7000, Mons, Belgium
| | - Ivan Meeus
- Laboratory of Agrozoology, Department of Plants of Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Gent, Belgium
| | - Nicolas J Vereecken
- Agroecology Lab, Université libre de Bruxelles (ULB), Boulevard du Triomphe CP 264/02, 1050, Brussels, Belgium
| | - Denis Michez
- Laboratory of Zoology, Research Institute for Biosciences, University of Mons, Place du parc 20, 7000, Mons, Belgium
| | - Guy Smagghe
- Laboratory of Agrozoology, Department of Plants of Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Gent, Belgium
| | - Peter Vandamme
- Laboratory of Microbiology, Department of Biochemistry and Microbiology, Faculty of Sciences, Ghent University, K.L. Ledeganckstraat 35, 9000, Ghent, Belgium.
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2
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Rutkowski D, Weston M, Vannette RL. Bees just wanna have fungi: a review of bee associations with nonpathogenic fungi. FEMS Microbiol Ecol 2023; 99:fiad077. [PMID: 37422442 PMCID: PMC10370288 DOI: 10.1093/femsec/fiad077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 06/15/2023] [Accepted: 07/06/2023] [Indexed: 07/10/2023] Open
Abstract
Bee-fungus associations are common, and while most studies focus on entomopathogens, emerging evidence suggests that bees associate with a variety of symbiotic fungi that can influence bee behavior and health. Here, we review nonpathogenic fungal taxa associated with different bee species and bee-related habitats. We synthesize results of studies examining fungal effects on bee behavior, development, survival, and fitness. We find that fungal communities differ across habitats, with some groups restricted mostly to flowers (Metschnikowia), while others are present almost exclusively in stored provisions (Zygosaccharomyces). Starmerella yeasts are found in multiple habitats in association with many bee species. Bee species differ widely in the abundance and identity of fungi hosted. Functional studies suggest that yeasts affect bee foraging, development, and pathogen interactions, though few bee and fungal taxa have been examined in this context. Rarely, fungi are obligately beneficial symbionts of bees, whereas most are facultative bee associates with unknown or ecologically contextual effects. Fungicides can reduce fungal abundance and alter fungal communities associated with bees, potentially disrupting bee-fungi associations. We recommend that future study focus on fungi associated with non-honeybee species and examine multiple bee life stages to document fungal composition, abundance, and mechanistic effects on bees.
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Affiliation(s)
- Danielle Rutkowski
- 367 Briggs Hall, Department of Entomology and Nematology, University of California Davis, Davis, CA 95616, United States
| | - Makena Weston
- 367 Briggs Hall, Department of Entomology and Nematology, University of California Davis, Davis, CA 95616, United States
| | - Rachel L Vannette
- 367 Briggs Hall, Department of Entomology and Nematology, University of California Davis, Davis, CA 95616, United States
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3
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Strange JP, Tripodi AD, Huntzinger C, Knoblett J, Klinger E, Herndon JD, Vuong HQ, McFrederick QS, Irwin RE, Evans JD, Giacomini JJ, Ward R, Adler LS. Comparative analysis of 3 pollen sterilization methods for feeding bumble bees. JOURNAL OF ECONOMIC ENTOMOLOGY 2023; 116:662-673. [PMID: 36930576 DOI: 10.1093/jee/toad036] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 01/24/2023] [Accepted: 02/07/2023] [Indexed: 06/14/2023]
Abstract
Pollen is an essential component of bee diets, and rearing bumble bees (Bombus spp.) for commercial use necessitates feeding pollen in mass quantities. This pollen is collected from honey bee (Apis mellifera L.) colonies because neither an artificial diet nor an economical, large-scale pollen collection process from flowers is available. The provenance of honey bee-collected pollen is often unknown, and in some cases has crossed international borders. Both deformed wing virus (DWV) and the fungal pathogen Ascosphaera apis (Claussen) Olive & Spiltoir (cause of chalkbrood disease); occur in honey bee-collected pollen, and infections have been observed in bumble bees. We used these pathogens as general surrogates for viruses and spore-forming fungal diseases to test the efficacy of 3 sterilization methods, and assessed whether treatment altered pollen quality for the bumble bee. Using honey bee-collected pollen spiked with known doses of DWV and A. apis, we compared gamma irradiation (GI), ozone fumigation (OZ), and ethylene oxide fumigation (EO) against an untreated positive control and a negative control. Following sterilization treatments, we tested A. apis spore viability, detected viral presence with PCR, and tested palatability to the bumble bee Bombus impatiens Cresson. We also measured bacterial growth from pollens treated with EO and GI. GI and EO outperformed OZ treatment in pathogen suppression. EO had the highest sterilizing properties under commercial conditions and retained palatability and supported bee development better than other treatments. These results suggest that EO sterilization reduces pathogen risks while retaining pollen quality as a food source for rearing bumble bees.
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Affiliation(s)
- James P Strange
- USDA-ARS-Pollinating Insect Biology Management and Systematics Research Unit, Logan, UT 84341, United States
- Department of Entomology, The Ohio State University, Columbus, OH 43210, United States
| | | | - Craig Huntzinger
- USDA-ARS-Pollinating Insect Biology Management and Systematics Research Unit, Logan, UT 84341, United States
| | - Joyce Knoblett
- USDA-ARS-Pollinating Insect Biology Management and Systematics Research Unit, Logan, UT 84341, United States
| | - Ellen Klinger
- USDA-ARS-Pollinating Insect Biology Management and Systematics Research Unit, Logan, UT 84341, United States
- Department of Entomology, The Ohio State University, Columbus, OH 43210, United States
| | - James D Herndon
- USDA-ARS-Pollinating Insect Biology Management and Systematics Research Unit, Logan, UT 84341, United States
- Department of Biology, Utah State University, Logan, UT 84321, United States
| | - Hoang Q Vuong
- Department of Entomology, University of California, Riverside, Riverside, CA 92521, United States
| | - Quinn S McFrederick
- Department of Entomology, University of California, Riverside, Riverside, CA 92521, United States
| | - Rebecca E Irwin
- Department of Applied Ecology, NC State University, Raleigh, NC 27695United States
| | - Jay D Evans
- Bee Research Laboratory, Beltsville Agricultural Research Center, US Department of Agriculture, Beltsville, MD 20705, United States
| | - Jonathan J Giacomini
- Department of Applied Ecology, NC State University, Raleigh, NC 27695United States
| | - Robert Ward
- Department of Nutrition, Dietetics and Food Sciences, Utah State University, Logan, UT 84322United States
| | - Lynn S Adler
- Department of Biology, University of Massachusetts, Amherst, MA 01003United States
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4
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Chesters D, Liu X, Bell KL, Orr MC, Xie T, Zhou Q, Zhu C. An integrative bioinformatics pipeline shows that honeybee-associated microbiomes are driven primarily by pollen composition. INSECT SCIENCE 2023; 30:555-568. [PMID: 36001735 DOI: 10.1111/1744-7917.13104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 07/11/2022] [Accepted: 07/24/2022] [Indexed: 06/15/2023]
Abstract
The microbiomes associated with bee nests influence colony health through various mechanisms, although it is not yet clear how honeybee congeners differ in microbiome assembly processes, in particular the degrees to which floral visitations and the environment contribute to different aspects of diversity. We used DNA metabarcoding to sequence bacterial 16S rRNA from honey and stored pollen from nests of 4 honeybee species (Apis cerana, A. dorsata, A. florea, and A. laboriosa) sampled throughout Yunnan, China, a global biodiversity hotspot. We developed a computational pipeline integrating multiple databases for quantifying key facets of diversity, including compositional, taxonomic, phylogenetic, and functional ones. Further, we assessed candidate drivers of observed microbiome dissimilarity, particularly differences in floral visitations, habitat disturbance, and other key environmental variables. Analyses revealed that microbiome alpha diversity was broadly equivalent across the study sites and between bee species, apart from functional diversity which was very low in nests of the reclusive A. laboriosa. Turnover in microbiome composition across Yunnan was driven predominantly by pollen composition. Human disturbance negatively impacted both compositional and phylogenetic alpha diversity of nest microbiomes, but did not correlate with microbial turnover. We herein make progress in understanding microbiome diversity associated with key pollinators in a biodiversity hotspot, and provide a model for the use of a comprehensive informatics framework in assessing pattern and drivers of diversity, which enables the inclusion of explanatory variables both subtly and fundamentally different and enables elucidation of emergent or unexpected drivers.
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Affiliation(s)
- Douglas Chesters
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- International College, University of Chinese Academy of Sciences, Beijing, China
| | - Xiuwei Liu
- Institute of Agro-Products Processing, Yunnan Province Academy of Agricultural Science, Kunming, China
| | - Karen L Bell
- School of Biological Sciences, University of Western Australia, Crawley, WA, Australia
- CSIRO Health & Biosecurity, Floreat, WA, Australia
| | - Michael C Orr
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- International College, University of Chinese Academy of Sciences, Beijing, China
| | - Tingting Xie
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, Anhui Normal University, Wuhu, Anhui Province, China
| | - Qingsong Zhou
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Chaodong Zhu
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- International College, University of Chinese Academy of Sciences, Beijing, China
- State Key Laboratory of Integrated Pest Management, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- College of Biological Sciences, University of Chinese Academy of Sciences, Beijing, China
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5
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Kueneman JG, Gillung J, Van Dyke MT, Fordyce RF, Danforth BN. Solitary bee larvae modify bacterial diversity of pollen provisions in the stem-nesting bee, Osmia cornifrons (Megachilidae). Front Microbiol 2023; 13:1057626. [PMID: 36699601 PMCID: PMC9868615 DOI: 10.3389/fmicb.2022.1057626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 12/13/2022] [Indexed: 01/11/2023] Open
Abstract
Microbes, including diverse bacteria and fungi, play an important role in the health of both solitary and social bees. Among solitary bee species, in which larvae remain in a closed brood cell throughout development, experiments that modified or eliminated the brood cell microbiome through sterilization indicated that microbes contribute substantially to larval nutrition and are in some cases essential for larval development. To better understand how feeding larvae impact the microbial community of their pollen/nectar provisions, we examine the temporal shift in the bacterial community in the presence and absence of actively feeding larvae of the solitary, stem-nesting bee, Osmia cornifrons (Megachilidae). Our results indicate that the O. cornifrons brood cell bacterial community is initially diverse. However, larval solitary bees modify the microbial community of their pollen/nectar provisions over time by suppressing or eliminating rare taxa while favoring bacterial endosymbionts of insects and diverse plant pathogens, perhaps through improved conditions or competitive release. We suspect that the proliferation of opportunistic plant pathogens may improve nutrient availability of developing larvae through degradation of pollen. Thus, the health and development of solitary bees may be interconnected with pollen bacterial diversity and perhaps with the propagation of plant pathogens.
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Affiliation(s)
- Jordan G. Kueneman
- Danforth Lab, Department of Entomology, Cornell University, Ithaca, NY, United States,*Correspondence: Jordan G. Kueneman, ✉
| | - Jessica Gillung
- Danforth Lab, Department of Entomology, Cornell University, Ithaca, NY, United States,Lyman Entomological Museum, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
| | - Maria T. Van Dyke
- Danforth Lab, Department of Entomology, Cornell University, Ithaca, NY, United States
| | - Rachel F. Fordyce
- Danforth Lab, Department of Entomology, Cornell University, Ithaca, NY, United States
| | - Bryan N. Danforth
- Danforth Lab, Department of Entomology, Cornell University, Ithaca, NY, United States
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6
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Leonhardt SD, Peters B, Keller A. Do amino and fatty acid profiles of pollen provisions correlate with bacterial microbiomes in the mason bee Osmia bicornis? Philos Trans R Soc Lond B Biol Sci 2022; 377:20210171. [PMID: 35491605 DOI: 10.1098/rstb.2021.0171] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Bee performance and well-being strongly depend on access to sufficient and appropriate resources, in particular pollen and nectar of flowers, which constitute the major basis of bee nutrition. Pollen-derived microbes appear to play an important but still little explored role in the plant pollen-bee interaction dynamics, e.g. through affecting quantities and ratios of important nutrients. To better understand how microbes in pollen collected by bees may affect larval health through nutrition, we investigated correlations between the floral, bacterial and nutritional composition of larval provisions and the gut bacterial communities of the solitary megachilid bee Osmia bicornis. Our study reveals correlations between the nutritional quality of pollen provisions and the complete bacterial community as well as individual members of both pollen provisions and bee guts. In particular pollen fatty acid profiles appear to interact with specific members of the pollen bacterial community, indicating that pollen-derived bacteria may play an important role in fatty acid provisioning. As increasing evidence suggests a strong effect of dietary fatty acids on bee performance, future work should address how the observed interactions between specific fatty acids and the bacterial community in larval provisions relate to health in O. bicornis. This article is part of the theme issue 'Natural processes influencing pollinator health: from chemistry to landscapes'.
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Affiliation(s)
- Sara Diana Leonhardt
- Plant-Insect Interactions, TUM School of Life Science Systems, Technical University of Munich, Freising, Germany
| | - Birte Peters
- Department for Animal Ecology and Tropical Biology, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany.,Center for Computational and Theoretical Biology, University of Würzburg, Emil Fischer Strasse, 97074 Würzburg, Germany
| | - Alexander Keller
- Cellular and Organismic Networks, Faculty of Biology, Ludwig-Maximilians-Universität Munich, 82152 Planegg-Martinsried, Germany
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7
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Gaiarsa MP, Rehan S, Barbour MA, McFrederick QS. Individual dietary specialization in a generalist bee varies across populations but has no effect on the richness of associated microbial communities. Am Nat 2022; 200:730-737. [DOI: 10.1086/721023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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8
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Dharampal PS, Danforth BN, Steffan SA. Exosymbiotic microbes within fermented pollen provisions are as important for the development of solitary bees as the pollen itself. Ecol Evol 2022; 12:e8788. [PMID: 35414891 PMCID: PMC8986510 DOI: 10.1002/ece3.8788] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 03/11/2022] [Accepted: 03/14/2022] [Indexed: 11/26/2022] Open
Abstract
Developing bees derive significant benefits from the microbes present within their guts and fermenting pollen provisions. External microbial symbionts (exosymbionts) associated with larval diets may be particularly important for solitary bees that suffer reduced fitness when denied microbe‐colonized pollen. To investigate whether this phenomenon is generalizable across foraging strategy, we examined the effects of exosymbiont presence/absence across two solitary bee species, a pollen specialist and generalist. Larvae from each species were reared on either microbe‐rich natural or microbe‐deficient sterilized pollen provisions allocated by a female forager belonging to their own species (conspecific‐sourced pollen) or that of another species (heterospecific‐sourced pollen). Our results reveal that the presence of pollen‐associated microbes was critical for the survival of both the generalist and specialist larvae, regardless of whether the pollen was sourced from a conspecific or heterospecific forager. Given the positive effects of exosymbiotic microbes for larval fitness, we then examined if the magnitude of this benefit varied based on whether the microbes were provisioned by a conspecific forager (the mother bee) or a heterospecific forager. In this second study, generalist larvae were reared only on microbe‐rich pollen provisions, but importantly, the sources (conspecific versus heterospecific) of the microbes and pollen were experimentally manipulated. Bee fitness metrics indicated that microbial and pollen sourcing both had significant impacts on larval performance, and the effect sizes of each were similar. Moreover, the effects of conspecific‐sourced microbes and conspecific‐sourced pollen were strongly positive, while that of heterospecific‐sourced microbes and heterospecific‐sourced pollen, strongly negative. Our findings imply that not only is the presence of exosymbionts critical for both specialist and generalist solitary bees, but more notably, that the composition of the specific microbial community within larval pollen provisions may be as critical for bee development as the composition of the pollen itself.
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Affiliation(s)
| | | | - Shawn A. Steffan
- Department of Entomology University of Wisconsin Madison Wisconsin USA
- USDA‐ARS Vegetable Crops Research Unit Madison Wisconsin USA
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9
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Abstract
Diet and gut microbiomes are intricately linked on both short and long timescales. Changes in diet can alter the microbiome, while microbes in turn allow hosts to access novel diets. Bees are wasps that switched to a vegetarian lifestyle, and the vast majority of bees feed on pollen and nectar. Some stingless bee species, however, also collect carrion, and a few have fully reverted to a necrophagous lifestyle, relying on carrion for protein and forgoing flower visitation altogether. These “vulture” bees belong to the corbiculate apid clade, which is known for its ancient association with a small group of core microbiome phylotypes. Here, we investigate the vulture bee microbiome, along with closely related facultatively necrophagous and obligately pollinivorous species, to understand how these diets interact with microbiome structure. Via deep sequencing of the 16S rRNA gene and subsequent community analyses, we find that vulture bees have lost some core microbes, retained others, and entered into novel associations with acidophilic microbes found in the environment and on carrion. The abundance of acidophilic bacteria suggests that an acidic gut is important for vulture bee nutrition and health, as has been found in other carrion-feeding animals. Facultatively necrophagous bees have more variable microbiomes than strictly pollinivorous bees, suggesting that bee diet may interact with microbiomes on both short and long timescales. Further study of vulture bees promises to provide rich insights into the role of the microbiome in extreme diet switches.
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10
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Cecala JM, Wilson Rankin EE. Petals and leaves: quantifying the use of nest building materials by the world's most valuable solitary bee. Ecology 2021; 103:e03584. [PMID: 34767257 DOI: 10.1002/ecy.3584] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 09/07/2021] [Accepted: 09/22/2021] [Indexed: 11/06/2022]
Affiliation(s)
- Jacob M Cecala
- Department of Entomology, University of California, Riverside, California, 92521, USA
| | - Erin E Wilson Rankin
- Department of Entomology, University of California, Riverside, California, 92521, USA
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11
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Microbiome of the wasp Vespula pensylvanica in native and invasive populations, and associations with Moku virus. PLoS One 2021; 16:e0255463. [PMID: 34324610 PMCID: PMC8321129 DOI: 10.1371/journal.pone.0255463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 07/16/2021] [Indexed: 11/19/2022] Open
Abstract
Invasive species present a worldwide concern as competition and pathogen reservoirs for native species. Specifically, the invasive social wasp, Vespula pensylvanica, is native to western North America and has become naturalized in Hawaii, where it exerts pressures on native arthropod communities as a competitor and predator. As invasive species may alter the microbial and disease ecology of their introduced ranges, there is a need to understand the microbiomes and virology of social wasps. We used 16S rRNA gene sequencing to characterize the microbiome of V. pensylvanica samples pooled by colony across two geographically distinct ranges and found that wasps generally associate with taxa within the bacterial genera Fructobacillus, Fructilactobacillus, Lactococcus, Leuconostoc, and Zymobacter, and likely associate with environmentally-acquired bacteria. Furthermore, V. pensylvanica harbors-and in some cases were dominated by-many endosymbionts including Wolbachia, Sodalis, Arsenophonus, and Rickettsia, and were found to contain bee-associated taxa, likely due to scavenging on or predation upon honey bees. Next, we used reverse-transcriptase quantitative PCR to assay colony-level infection intensity for Moku virus (family: Iflaviridae), a recently-described disease that is known to infect multiple Hymenopteran species. While Moku virus was prevalent and in high titer, it did not associate with microbial diversity, indicating that the microbiome may not directly interact with Moku virus in V. pensylvanica in meaningful ways. Collectively, our results suggest that the invasive social wasp V. pensylvanica associates with a simple microbiome, may be infected with putative endosymbionts, likely acquires bacterial taxa from the environment and diet, and is often infected with Moku virus. Our results suggest that V. pensylvanica, like other invasive social insects, has the potential to act as a reservoir for bacteria pathogenic to other pollinators, though this requires experimental demonstration.
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12
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The bacterial and fungal nest microbiomes in populations of the social spider Stegodyphus dumicola. Syst Appl Microbiol 2021; 44:126222. [PMID: 34146923 DOI: 10.1016/j.syapm.2021.126222] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 05/09/2021] [Accepted: 05/26/2021] [Indexed: 12/17/2022]
Abstract
Social spiders of the species Stegodyphus dumicola live in communal nests with hundreds of individuals and are characterized by extremely low species-wide genetic diversity. The lack of genetic diversity in combination with group living imposes a potential threat for infection by pathogens. We therefore proposed that specific microbial symbionts inhabiting the spider nests may provide antimicrobial defense. To compare the bacterial and fungal diversity in 17 nests from three different locations in Namibia, we used 16S rRNA gene and internal transcribed spacer (ITS2) sequencing. The nest microbiomes differed between geographically distinct spider populations and appeared largely determined by the local environment. Nevertheless, we identified a core microbiome consisting of four bacterial genera (Curtobacterium, Modestobacter, Sphingomonas, Massilia) and four fungal genera (Aureobasidium, Didymella, Alternaria, Ascochyta), which likely are selected from surrounding soil and plants by the nest environment. We did not find indications for a strain- or species-specific symbiosis in the nests. Isolation of bacteria and fungi from nest material retrieved a few bacterial strains with antimicrobial activity but a number of antimicrobial fungi, including members of the fungal core microbiome. The significance of antimicrobial taxa in the nest microbiome for host protection remains to be shown.
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13
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Mayr AV, Keller A, Peters MK, Grimmer G, Krischke B, Geyer M, Schmitt T, Steffan‐Dewenter I. Cryptic species and hidden ecological interactions of halictine bees along an elevational gradient. Ecol Evol 2021; 11:7700-7712. [PMID: 34188845 PMCID: PMC8216903 DOI: 10.1002/ece3.7605] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 03/29/2021] [Accepted: 03/31/2021] [Indexed: 11/07/2022] Open
Abstract
Changes of abiotic and biotic conditions along elevational gradients represent serious challenges to organisms which may promote the turnover of species, traits and biotic interaction partners. Here, we used molecular methods to study cuticular hydrocarbon (CHC) profiles, biotic interactions and phylogenetic relationships of halictid bees of the genus Lasioglossum along a 2,900 m elevational gradient at Mt. Kilimanjaro, Tanzania. We detected a strong species turnover of morphologically indistinguishable taxa with phylogenetically clustered cryptic species at high elevations, changes in CHC profiles, pollen resource diversity, and a turnover in the gut and body surface microbiome of bees. At high elevations, increased proportions of saturated compounds in CHC profiles indicate physiological adaptations to prevent desiccation. More specialized diets with higher proportions of low-quality Asteraceae pollen imply constraints in the availability of food resources. Interactive effects of climatic conditions on gut and surface microbiomes, CHC profiles, and pollen diet suggest complex feedbacks among abiotic conditions, ecological interactions, physiological adaptations, and phylogenetic constraints as drivers of halictid bee communities at Mt. Kilimanjaro.
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Affiliation(s)
- Antonia V. Mayr
- Department of Animal Ecology and Tropical BiologyBiocenterUniversity of WürzburgWürzburgGermany
| | - Alexander Keller
- Department of Animal Ecology and Tropical BiologyBiocenterUniversity of WürzburgWürzburgGermany
- Center for Computational and Theoretical BiologyCampus NordUniversity of WürzburgWürzburgGermany
- Department of BioinformaticsBiocenterUniversity of WürzburgWürzburgGermany
| | - Marcell K. Peters
- Department of Animal Ecology and Tropical BiologyBiocenterUniversity of WürzburgWürzburgGermany
| | - Gudrun Grimmer
- Department of Animal Ecology and Tropical BiologyBiocenterUniversity of WürzburgWürzburgGermany
| | - Beate Krischke
- Department of Animal Ecology and Tropical BiologyBiocenterUniversity of WürzburgWürzburgGermany
| | - Mareen Geyer
- Department of Animal Ecology and Tropical BiologyBiocenterUniversity of WürzburgWürzburgGermany
| | - Thomas Schmitt
- Department of Animal Ecology and Tropical BiologyBiocenterUniversity of WürzburgWürzburgGermany
| | - Ingolf Steffan‐Dewenter
- Department of Animal Ecology and Tropical BiologyBiocenterUniversity of WürzburgWürzburgGermany
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14
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Moreira EA, Persinoti GF, Menezes LR, Paixão DAA, Alvarez TM, Cairo JPLF, Squina FM, Costa-Leonardo AM, Rodrigues A, Sillam-Dussès D, Arab A. Complementary Contribution of Fungi and Bacteria to Lignocellulose Digestion in the Food Stored by a Neotropical Higher Termite. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.632590] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Lignocellulose digestion in termites is achieved through the functional synergy between gut symbionts and host enzymes. However, some species have evolved additional associations with nest microorganisms that collaborate in the decomposition of plant biomass. In a previous study, we determined that plant material packed with feces inside the nests of Cornitermes cumulans (Syntermitinae) harbors a distinct microbial assemblage. These food nodules also showed a high hemicellulolytic activity, possibly acting as an external place for complementary lignocellulose digestion. In this study, we used a combination of ITS sequence analysis, metagenomics, and metatranscriptomics to investigate the presence and differential expression of genes coding for carbohydrate-active enzymes (CAZy) in the food nodules and the gut of workers and soldiers. Our results confirm that food nodules express a distinct set of CAZy genes suggesting that stored plant material is initially decomposed by enzymes that target the lignin and complex polysaccharides from fungi and bacteria before the passage through the gut, where it is further targeted by a complementary set of cellulases, xylanases, and esterases produced by the gut microbiota and the termite host. We also showed that the expression of CAZy transcripts associated to endoglucanases and xylanases was higher in the gut of termites than in the food nodules. An additional finding in this study was the presence of fungi in the termite gut that expressed CAZy genes. This study highlights the importance of externalization of digestion by nest microbes and provides new evidence of complementary digestion in the context of higher termite evolution.
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Daisley BA, Reid G. BEExact: a Metataxonomic Database Tool for High-Resolution Inference of Bee-Associated Microbial Communities. mSystems 2021; 6:e00082-21. [PMID: 33824193 PMCID: PMC8546966 DOI: 10.1128/msystems.00082-21] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 03/08/2021] [Indexed: 01/04/2023] Open
Abstract
High-throughput 16S rRNA gene sequencing technologies have robust potential to improve our understanding of bee (Hymenoptera: Apoidea)-associated microbial communities and their impact on hive health and disease. Despite recent computation algorithms now permitting exact inferencing of high-resolution exact amplicon sequence variants (ASVs), the taxonomic classification of these ASVs remains a challenge due to inadequate reference databases. To address this, we assemble a comprehensive data set of all publicly available bee-associated 16S rRNA gene sequences, systematically annotate poorly resolved identities via inclusion of 618 placeholder labels for uncultivated microbial dark matter, and correct for phylogenetic inconsistencies using a complementary set of distance-based and maximum likelihood correction strategies. To benchmark the resultant database (BEExact), we compare performance against all existing reference databases in silico using a variety of classifier algorithms to produce probabilistic confidence scores. We also validate realistic classification rates on an independent set of ∼234 million short-read sequences derived from 32 studies encompassing 50 different bee types (36 eusocial and 14 solitary). Species-level classification rates on short-read ASVs range from 80 to 90% using BEExact (with ∼20% due to "bxid" placeholder names), whereas only ∼30% at best can be resolved with current universal databases. A series of data-driven recommendations are developed for future studies. We conclude that BEExact (https://github.com/bdaisley/BEExact) enables accurate and standardized microbiota profiling across a broad range of bee species-two factors of key importance to reproducibility and meaningful knowledge exchange within the scientific community that together, can enhance the overall utility and ecological relevance of routine 16S rRNA gene-based sequencing endeavors.IMPORTANCE The failure of current universal taxonomic databases to support the rapidly expanding field of bee microbiota research has led to many investigators relying on "in-house" reference sets or manual classification of sequence reads (usually based on BLAST searches), often with vague identity thresholds and subjective taxonomy choices. This time-consuming, error- and bias-prone process lacks standardization, cripples the potential for comparative cross-study analysis, and in many cases is likely to incorrectly sway study conclusions. BEExact is structured on and leverages several complementary bioinformatic techniques to enable refined inference of bee host-associated microbial communities without any other methodological modifications necessary. It also bridges the gap between current practical outcomes (i.e., phylotype-to-genus level constraints with 97% operational taxonomic units [OTUs]) and the theoretical resolution (i.e., species-to-strain level classification with 100% ASVs) attainable in future microbiota investigations. Other niche habitats could also likely benefit from customized database curation via implementation of the novel approaches introduced in this study.
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Affiliation(s)
- Brendan A Daisley
- Department of Microbiology & Immunology, The University of Western Ontario, London, Ontario, Canada
- Canadian Centre for Human Microbiome and Probiotics Research, London, Ontario, Canada
| | - Gregor Reid
- Department of Microbiology & Immunology, The University of Western Ontario, London, Ontario, Canada
- Canadian Centre for Human Microbiome and Probiotics Research, London, Ontario, Canada
- Department of Surgery, Schulich School of Medicine, London, Ontario, Canada
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16
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Francis JS, Tatarko AR, Richman SK, Vaudo AD, Leonard AS. Microbes and pollinator behavior in the floral marketplace. CURRENT OPINION IN INSECT SCIENCE 2021; 44:16-22. [PMID: 33075580 DOI: 10.1016/j.cois.2020.10.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/07/2020] [Accepted: 10/08/2020] [Indexed: 06/11/2023]
Abstract
Pollinator foraging decisions shape microbial dispersal, and microbes change floral phenotypes in ways perceivable by pollinators. Yet, the role microbes play in the cognitive ecology of pollination is relatively unexplored. Reviewing recent literature on floral microbial ecology and pollinator behavior, we advocate for further integration between these two fields. Insights into pollinator learning, memory, and decision-making can help explain their responses to microbially-altered floral phenotypes. Specifically, considering how pollinators forage for multiple nutrients, cope with uncertainty, structure foraging bouts, and move through their environment could inform predictions about microbial dispersal within plant communities. We highlight how behavior connects microbial changes in floral phenotype to downstream effects on both microbial dispersal and plant fitness.
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Affiliation(s)
- Jacob S Francis
- Ecology, Evolution and Conservation Biology Graduate Program, University of Nevada, Reno, 1664 N. Virginia St., Reno, NV 89557, United States
| | - Anna R Tatarko
- Ecology, Evolution and Conservation Biology Graduate Program, University of Nevada, Reno, 1664 N. Virginia St., Reno, NV 89557, United States
| | - Sarah K Richman
- Department of Biology, MS-314, University of Nevada, Reno, 1664 N. Virginia St., Reno, NV 89557, United States
| | - Anthony D Vaudo
- Department of Biology, MS-314, University of Nevada, Reno, 1664 N. Virginia St., Reno, NV 89557, United States
| | - Anne S Leonard
- Department of Biology, MS-314, University of Nevada, Reno, 1664 N. Virginia St., Reno, NV 89557, United States.
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17
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Adler LS, Irwin RE, McArt SH, Vannette RL. Floral traits affecting the transmission of beneficial and pathogenic pollinator-associated microbes. CURRENT OPINION IN INSECT SCIENCE 2021; 44:1-7. [PMID: 32866657 PMCID: PMC7914268 DOI: 10.1016/j.cois.2020.08.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 08/17/2020] [Accepted: 08/19/2020] [Indexed: 05/22/2023]
Abstract
Flowers provide resources for pollinators, and can also be transmission venues for beneficial or pathogenic pollinator-associated microbes. Floral traits could mediate transmission similarly for beneficial and pathogenic microbes, although some beneficial microbes can grow in flowers while pathogenic microbes may only survive until acquired by a new host. In spite of conceptual similarities, research on beneficial and pathogenic pollinator-associated microbes has progressed mostly independently. Recent advances demonstrate that floral traits are associated with transmission of beneficial and pathogenic microbes, with consequences for pollinator populations and communities. However, there is a near-absence of experimental manipulations of floral traits to determine causal effects on transmission, and a need to understand how floral, microbe and host traits interact to mediate transmission.
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Affiliation(s)
- Lynn S Adler
- Department of Biology, University of Massachusetts, 221 Morrill Science Center, 611 N. Pleasant St., Amherst MA 01002 USA.
| | - Rebecca E Irwin
- Department of Applied Ecology, North Carolina State University, 127 David Clark Labs, 100 Eugene Brooks Ave., Raleigh, NC 27695 USA
| | - Scott H McArt
- Department of Entomology, Cornell University, 4132 Comstock Hall, 129 Garden Ave., Ithaca, NY 14853 USA
| | - Rachel L Vannette
- Department of Entomology and Nematology, University of California, 43 Briggs Hall, Davis CA 95616 USA
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18
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Pozo MI, Mariën T, van Kemenade G, Wäckers F, Jacquemyn H. Effects of pollen and nectar inoculation by yeasts, bacteria or both on bumblebee colony development. Oecologia 2021; 195:689-703. [PMID: 33582870 DOI: 10.1007/s00442-021-04872-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 02/03/2021] [Indexed: 11/28/2022]
Abstract
It is increasingly recognized that gut microbiota have a major effect on the physiology, biology, ecology and evolution of their animal hosts. Because in social insects, the gut microbiota is acquired through the diet and by contact with nest provisions, it can be hypothesized that regular supplementation of microorganisms to the diet will have an impact on the fitness of the consumer and on the development of the whole colony. To test this hypothesis, we investigated how supplementation of bacteria, yeasts, and combinations of the two to either pollen or nectar affected colony development in the social bumblebee Bombus terrestris. Three yeasts and three bacterial species that live at the flower-insect interface were used in the experiments and the development of bumblebee colonies was monitored over a period of 10 weeks. The results showed that administration of microbes via pollen had a stronger positive impact on colony development than when provided via sugar water. Supplementation of bacteria led, in general, to a faster egg laying, higher brood size and increased production of workers during the first weeks, whereas yeasts or a combination of yeasts and bacteria had less impact on colony development. However, the results differed between microbial species, with Wickerhamiella bombiphila and Rosenbergiella nectarea showing the strongest increase in colony development. Torulaspora delbrueckii induced early male production, which is likely a fitness cost. We conclude that the tested bacteria-yeast consortia did not result in better colony development than the interacting species alone.
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Affiliation(s)
- María I Pozo
- Biology Department, Plant Conservation and Population Biology, KU Leuven, 3001, Heverlee, Belgium.
| | - Toon Mariën
- Biology Department, Plant Conservation and Population Biology, KU Leuven, 3001, Heverlee, Belgium
| | - Gaby van Kemenade
- Biology Department, Plant Conservation and Population Biology, KU Leuven, 3001, Heverlee, Belgium.,Biobest Group, Research and Development, 2260, Westerlo, Belgium
| | - Felix Wäckers
- Biobest Group, Research and Development, 2260, Westerlo, Belgium
| | - Hans Jacquemyn
- Biology Department, Plant Conservation and Population Biology, KU Leuven, 3001, Heverlee, Belgium
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19
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Kapheim KM, Johnson MM, Jolley M. Composition and acquisition of the microbiome in solitary, ground-nesting alkali bees. Sci Rep 2021; 11:2993. [PMID: 33542351 PMCID: PMC7862682 DOI: 10.1038/s41598-021-82573-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 01/21/2021] [Indexed: 01/30/2023] Open
Abstract
Increasing evidence suggests the microbiome plays an important role in bee ecology and health. However, the relationship between bees and their bacterial symbionts has only been explored in a handful of species. We characterized the microbiome across the life cycle of solitary, ground-nesting alkali bees (Nomia melanderi). We find that feeding status is a major determinant of microbiome composition. The microbiome of feeding larvae was similar to that of pollen provisions, but the microbiome of post-feeding larvae (pre-pupae) was similar to that of the brood cell walls and newly-emerged females. Feeding larvae and pollen provisions had the lowest beta diversity, suggesting the composition of larval diet is highly uniform. Comparisons between lab-reared, newly-emerged, and nesting adult females suggest that the hindgut bacterial community is largely shaped by the external environment. However, we also identified taxa that are likely acquired in the nest or which increase or decrease in relative abundance with age. Although Lactobacillus micheneri was highly prevalent in pollen provisions, it was only detected in one lab-reared female, suggesting it is primarily acquired from environmental sources. These results provide the foundation for future research on metagenomic function and development of probiotics for these native pollinators.
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Affiliation(s)
- Karen M. Kapheim
- grid.53857.3c0000 0001 2185 8768Department of Biology, Utah State University, Logan, UT 84322 USA
| | - Makenna M. Johnson
- grid.53857.3c0000 0001 2185 8768Department of Biology, Utah State University, Logan, UT 84322 USA
| | - Maggi Jolley
- grid.53857.3c0000 0001 2185 8768Department of Biology, Utah State University, Logan, UT 84322 USA
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20
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Rothman JA, Russell KA, Leger L, McFrederick QS, Graystock P. The direct and indirect effects of environmental toxicants on the health of bumblebees and their microbiomes. Proc Biol Sci 2020; 287:20200980. [PMID: 33109012 PMCID: PMC7661295 DOI: 10.1098/rspb.2020.0980] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 10/05/2020] [Indexed: 01/14/2023] Open
Abstract
Bumblebees (Bombus spp.) are important and widespread insect pollinators, but the act of foraging on flowers can expose them to harmful pesticides and chemicals such as oxidizers and heavy metals. How these compounds directly influence bee survival and indirectly affect bee health via the gut microbiome is largely unknown. As toxicants in floral nectar and pollen take many forms, we explored the genomes of bee-associated microbes for their potential to detoxify cadmium, copper, selenate, the neonicotinoid pesticide imidacloprid, and hydrogen peroxide-which have all been identified in floral nectar and pollen. We then exposed Bombus impatiens workers to varying concentrations of these chemicals via their diet and assayed direct effects on bee survival. Using field-realistic doses, we further explored the indirect effects on bee microbiomes. We found multiple putative genes in core gut microbes that may aid in detoxifying harmful chemicals. We also found that while the chemicals are largely toxic at levels within and above field-realistic concentrations, the field-realistic concentrations-except for imidacloprid-altered the composition of the bee microbiome, potentially causing gut dysbiosis. Overall, our study shows that chemicals found in floral nectar and pollen can cause bee mortality, and likely have indirect, deleterious effects on bee health via their influence on the bee microbiome.
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Affiliation(s)
- Jason A. Rothman
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697, USA
- Department of Entomology, University of California, Riverside, CA 92521, USA
| | - Kaleigh A. Russell
- Department of Entomology, University of California, Riverside, CA 92521, USA
| | - Laura Leger
- Department of Entomology, University of California, Riverside, CA 92521, USA
| | | | - Peter Graystock
- Department of Entomology, University of California, Riverside, CA 92521, USA
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot SL5 7PY, UK
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21
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Parasite defense mechanisms in bees: behavior, immunity, antimicrobials, and symbionts. Emerg Top Life Sci 2020; 4:59-76. [PMID: 32558901 DOI: 10.1042/etls20190069] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 11/14/2019] [Accepted: 11/26/2019] [Indexed: 12/11/2022]
Abstract
Parasites are linked to the decline of some bee populations; thus, understanding defense mechanisms has important implications for bee health. Recent advances have improved our understanding of factors mediating bee health ranging from molecular to landscape scales, but often as disparate literatures. Here, we bring together these fields and summarize our current understanding of bee defense mechanisms including immunity, immunization, and transgenerational immune priming in social and solitary species. Additionally, the characterization of microbial diversity and function in some bee taxa has shed light on the importance of microbes for bee health, but we lack information that links microbial communities to parasite infection in most bee species. Studies are beginning to identify how bee defense mechanisms are affected by stressors such as poor-quality diets and pesticides, but further research on this topic is needed. We discuss how integrating research on host traits, microbial partners, and nutrition, as well as improving our knowledge base on wild and semi-social bees, will help inform future research, conservation efforts, and management.
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22
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Diet Breadth Affects Bacterial Identity but Not Diversity in the Pollen Provisions of Closely Related Polylectic and Oligolectic Bees. INSECTS 2020; 11:insects11090645. [PMID: 32962223 PMCID: PMC7564857 DOI: 10.3390/insects11090645] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 09/02/2020] [Accepted: 09/17/2020] [Indexed: 12/18/2022]
Abstract
Simple Summary Solitary bees are important pollinators in managed and wild ecosystems. Across the bee phylogeny, bees may forage on a single species of plant, few plant species, or a broad diversity of plants. During foraging, these bees are often exposed to microbes, and in turn, may inoculate the brood cell and pollen provision of their offspring with these microbes. It is becoming evident that pollen-associated microbes are important to bee health, but it is not known how diet breadth impacts bees’ exposure to microbes. In this study, we collected pollen provisions from the bees Osmia lignaria and Osmia ribifloris at four different sites, then characterized the bacterial populations within the pollen provisions with 16S rRNA gene sequencing. We found that diet breadth did not have large effects on the bacteria found in the pollen provisions. We also note that the bacterial communities were slightly different between bee species and site, and there was minimal overlap in the unique bacterial variants between sites and bee species too. Our research supports the hypothesis of environmental transmission for solitary bee microbes, and we suggest future studies investigate the impacts of microbes on larval health. Abstract Mounting evidence suggests that microbes found in the pollen provisions of wild and solitary bees are important drivers of larval development. As these microbes are also known to be transmitted via the environment, most likely from flowers, the diet breadth of a bee may affect the diversity and identity of the microbes that occur in its pollen provisions. Here, we tested the hypothesis that, due to the importance of floral transmission of microbes, diet breadth affects pollen provision microbial community composition. We collected pollen provisions at four sites from the polylectic bee Osmia lignaria and the oligolectic bee Osmia ribifloris. We used high-throughput sequencing of the bacterial 16S rRNA gene to characterize the bacteria found in these provisions. We found minimal overlap in the specific bacterial variants in pollen provisions across the host species, even when the bees were constrained to foraging from the same flowers in cages at one site. Similarly, there was minimal overlap in the specific bacterial variants across sites, even within the same host species. Together, these findings highlight the importance of environmental transmission and host specific sorting influenced by diet breadth for microbes found in pollen provisions. Future studies addressing the functional consequences of this filtering, along with tests for differences between more species of oligoletic and polylectic bees will provide rich insights into the microbial ecology of solitary bees.
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23
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Dew RM, McFrederick QS, Rehan SM. Diverse Diets with Consistent Core Microbiome in Wild Bee Pollen Provisions. INSECTS 2020; 11:insects11080499. [PMID: 32759653 PMCID: PMC7469187 DOI: 10.3390/insects11080499] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 07/26/2020] [Accepted: 07/29/2020] [Indexed: 12/13/2022]
Abstract
Bees collect pollen from flowers for their offspring, and by doing so contribute critical pollination services for our crops and ecosystems. Unlike many managed bee species, wild bees are thought to obtain much of their microbiome from the environment. However, we know surprisingly little about what plant species bees visit and the microbes associated with the collected pollen. Here, we addressed the hypothesis that the pollen and microbial components of bee diets would change across the range of the bee, by amplicon sequencing pollen provisions of a widespread small carpenter bee, Ceratina calcarata, across three populations. Ceratina calcarata was found to use a diversity of floral resources across its range, but the bacterial genera associated with pollen provisions were very consistent. Acinetobacter, Erwinia, Lactobacillus, Sodalis, Sphingomonas and Wolbachia were among the top ten bacterial genera across all sites. Ceratina calcarata uses both raspberry (Rubus) and sumac (Rhus) stems as nesting substrates, however nests within these plants showed no preference for host plant pollen. Significant correlations in plant and bacterial co-occurrence differed between sites, indicating that many of the most common bacterial genera have either regional or transitory floral associations. This range-wide study suggests microbes present in brood provisions are conserved within a bee species, rather than mediated by climate or pollen composition. Moving forward, this has important implications for how these core bacteria affect larval health and whether these functions vary across space and diet. These data increase our understanding of how pollinators interact with and adjust to their changing environment.
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Affiliation(s)
- Rebecca M. Dew
- Department of Biology, York University, Toronto, ON M3J 1P3, Canada;
| | - Quinn S. McFrederick
- Department of Entomology, University of California Riverside, Riverside, CA 92521, USA;
| | - Sandra M. Rehan
- Department of Biology, York University, Toronto, ON M3J 1P3, Canada;
- Correspondence: ; Tel.: +1-416-736-2100
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24
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Voulgari-Kokota A, Steffan-Dewenter I, Keller A. Susceptibility of Red Mason Bee Larvae to Bacterial Threats Due to Microbiome Exchange with Imported Pollen Provisions. INSECTS 2020; 11:E373. [PMID: 32549328 PMCID: PMC7348846 DOI: 10.3390/insects11060373] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 06/12/2020] [Accepted: 06/13/2020] [Indexed: 12/22/2022]
Abstract
Solitary bees are subject to a variety of pressures that cause severe population declines. Currently, habitat loss, temperature shifts, agrochemical exposure, and new parasites are identified as major threats. However, knowledge about detrimental bacteria is scarce, although they may disturb natural microbiomes, disturb nest environments, or harm the larvae directly. To address this gap, we investigated 12 Osmia bicornis nests with deceased larvae and 31 nests with healthy larvae from the same localities in a 16S ribosomal RNA (rRNA) gene metabarcoding study. We sampled larvae, pollen provisions, and nest material and then contrasted bacterial community composition and diversity in healthy and deceased nests. Microbiomes of pollen provisions and larvae showed similarities for healthy larvae, whilst this was not the case for deceased individuals. We identified three bacterial taxa assigned to Paenibacillus sp. (closely related to P. pabuli/amylolyticus/xylanexedens), Sporosarcina sp., and Bacillus sp. as indicative for bacterial communities of deceased larvae, as well as Lactobacillus for corresponding pollen provisions. Furthermore, we performed a provisioning experiment, where we fed larvae with untreated and sterilized pollens, as well as sterilized pollens inoculated with a Bacillus sp. isolate from a deceased larva. Untreated larval microbiomes were consistent with that of the pollen provided. Sterilized pollen alone did not lead to acute mortality, while no microbiome was recoverable from the larvae. In the inoculation treatment, we observed that larval microbiomes were dominated by the seeded bacterium, which resulted in enhanced mortality. These results support that larval microbiomes are strongly determined by the pollen provisions. Further, they underline the need for further investigation of the impact of detrimental bacterial acquired via pollens and potential buffering by a diverse pollen provision microbiome in solitary bees.
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Affiliation(s)
- Anna Voulgari-Kokota
- Department of Bioinformatics, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany;
- Center for Computational and Theoretical Biology, Biocenter, University of Würzburg, Hubland Nord, 97074 Würzburg, Germany
- Current Address: Faculty of Science and Engineering, Groningen Institute for Evolutionary Life Sciences, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Ingolf Steffan-Dewenter
- Department of Animal Ecology and Tropical Biology, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany;
| | - Alexander Keller
- Department of Bioinformatics, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany;
- Center for Computational and Theoretical Biology, Biocenter, University of Würzburg, Hubland Nord, 97074 Würzburg, Germany
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25
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Vuong HQ, McFrederick QS. Comparative Genomics of Wild Bee and Flower Isolated Lactobacillus Reveals Potential Adaptation to the Bee Host. Genome Biol Evol 2020; 11:2151-2161. [PMID: 31243442 PMCID: PMC6685495 DOI: 10.1093/gbe/evz136] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/24/2019] [Indexed: 01/18/2023] Open
Abstract
Symbiosis with bacteria is common across insects, resulting in adaptive host phenotypes. The recently described bacterial symbionts Lactobacillus micheneri, Lactobacillus timberlakei, and Lactobacillus quenuiae are found in wild bee pollen provisions, bee guts, and flowers but have small genomes in comparison to other lactobacilli. We sequenced, assembled, and analyzed 27 new L. micheneri clade genomes to identify their possible ecological functions in flower and bee hosts. We determined possible key functions for the L. micheneri clade by identifying genes under positive selection, balancing selection, genes gained or lost, and population structure. A host adherence factor shows signatures of positive selection, whereas other orthologous copies are variable within the L. micheneri clade. The host adherence factors serve as strong evidence that these lactobacilli are adapted to animal hosts as their targets are found in the digestive tract of insects. Next, the L. micheneri clade is adapted toward a nutrient-rich environment, corroborating observations of where L. micheneri is most abundant. Additionally, genes involved in osmotolerance, pH tolerance, temperature resistance, detoxification, and oxidative stress response show signatures of selection that allow these bacteria to thrive in pollen and nectar masses in bee nests and in the bee gut. Altogether, these findings not only suggest that the L. micheneri clade is primarily adapted to the wild bee gut but also exhibit genomic features that would be beneficial to survival in flowers.
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Affiliation(s)
- Hoang Q Vuong
- Department of Entomology, University California Riverside.,Department of Plant Pathology and Microbiology, University California Riverside
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26
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Characterization of Anaerobic Rumen Fungal Community Composition in Yak, Tibetan Sheep and Small Tail Han Sheep Grazing on the Qinghai-Tibetan Plateau. Animals (Basel) 2020; 10:ani10010144. [PMID: 31963125 PMCID: PMC7023293 DOI: 10.3390/ani10010144] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 01/06/2020] [Accepted: 01/14/2020] [Indexed: 02/01/2023] Open
Abstract
Simple Summary Anaerobic rumen fungi play a vital role in fiber degradation. The objective of this study was to compare the anaerobic rumen fungal communities of full grazing ruminants in the Qinghai-Tibetan Plateau. Our results showed that the anaerobic rumen fungal community was affected by host species and the dynamic associations of them were host specific. This is the first study exploring the anaerobic rumen fungi in the full-grazing ruminants, which could lay a solid foundation to really identify fiber degradation fungal taxa using culture-dependent techniques in the future. Abstract The anaerobic rumen fungal community play a critical role in fibrous material degradation. However, there is a lack of data describing the composition of anaerobic rumen fungal community of full grazing ruminants in the Qinghai-Tibetan Plateau. For this reason, we employed the next-generation sequencing technique to elucidate the rumen fungal structure composition and evaluate the effects of host species on fungal communities. Community comparisons (Bray–Curtis index) between yak and Tibetan sheep revealed that the rumen fungal community was affected by host species (p < 0.05). The alpha diversity indices in the yak were significantly higher than in the Tibetan sheep and Small Tail Han sheep. Neocallimastigomycota was predominant regardless of host species. Within this phylum, unidentified genus of Neocallimastigaceae was the most dominant in all samples, followed by Piromyces and Orpinomyces. Moreover, the shared and unique OTUs in the rumen were identified and most of them belonged to the Orpinomyces. Co-occurrence network analysis identified that each animal species had their own keystone species and most of them were non-dominant flora. Our data indicate that host breeds override living environment as the key factor that determines fungal community in the rumen of grazing ruminants in the Qinghai-Tibetan Plateau.
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Rothman JA, Leger L, Kirkwood JS, McFrederick QS. Cadmium and Selenate Exposure Affects the Honey Bee Microbiome and Metabolome, and Bee-Associated Bacteria Show Potential for Bioaccumulation. Appl Environ Microbiol 2019; 85:e01411-19. [PMID: 31471302 PMCID: PMC6803295 DOI: 10.1128/aem.01411-19] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Accepted: 08/26/2019] [Indexed: 01/12/2023] Open
Abstract
Honey bees are important insect pollinators used heavily in agriculture and can be found in diverse environments. Bees may encounter toxicants such as cadmium and selenate by foraging on plants growing in contaminated areas, which can result in negative health effects. Honey bees are known to have a simple and consistent microbiome that conveys many benefits to the host, and toxicant exposure may impact this symbiotic microbial community. We used 16S rRNA gene sequencing to assay the effects that sublethal cadmium and selenate treatments had over 7 days and found that both treatments significantly but subtly altered the composition of the bee microbiome. Next, we exposed bees to cadmium and selenate and then used untargeted liquid chromatography-mass spectrometry (LC-MS) metabolomics to show that chemical exposure changed the bees' metabolite profiles and that compounds which may be involved in detoxification, proteolysis, and lipolysis were more abundant in treatments. Finally, we exposed several strains of bee-associated bacteria in liquid culture and found that each strain removed cadmium from its medium but that only Lactobacillus Firm-5 microbes assimilated selenate, indicating the possibility that these microbes may reduce the metal and metalloid burden on their host. Overall, our report shows that metal and metalloid exposure can affect the honey bee microbiome and metabolome and that strains of bee-associated bacteria can bioaccumulate these toxicants.IMPORTANCE Bees are important insect pollinators that may encounter environmental pollution when foraging upon plants grown in contaminated areas. Despite the pervasiveness of pollution, little is known about the effects of these toxicants on honey bee metabolism and their symbiotic microbiomes. Here, we investigated the impact of selenate and cadmium exposure on the gut microbiome and metabolome of honey bees. We found that exposure to these chemicals subtly altered the overall composition of the bees' microbiome and metabolome and that exposure to toxicants may negatively impact both host and microbe. As the microbiome of animals can reduce mortality upon metal or metalloid challenge, we grew bee-associated bacteria in media spiked with selenate or cadmium. We show that some bacteria can remove these toxicants from their media in vitro and suggest that bacteria may reduce metal burden in their hosts.
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Affiliation(s)
- Jason A Rothman
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, California, USA
- Department of Entomology, University of California, Riverside, Riverside, California, USA
| | - Laura Leger
- Department of Entomology, University of California, Riverside, Riverside, California, USA
| | - Jay S Kirkwood
- Metabolomics Core Facility, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, California, USA
| | - Quinn S McFrederick
- Department of Entomology, University of California, Riverside, Riverside, California, USA
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López-Uribe MM, Ricigliano VA, Simone-Finstrom M. Defining Pollinator Health: A Holistic Approach Based on Ecological, Genetic, and Physiological Factors. Annu Rev Anim Biosci 2019; 8:269-294. [PMID: 31618045 DOI: 10.1146/annurev-animal-020518-115045] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Evidence for global bee population declines has catalyzed a rapidly evolving area of research that aims to identify the causal factors and to effectively assess the status of pollinator populations. The term pollinator health emerged through efforts to understand causes of bee decline and colony losses, but it lacks a formal definition. In this review, we propose a definition for pollinator health and synthesize the available literature on the application of standardized biomarkers to assess health at the individual, colony, and population levels. We focus on biomarkers in honey bees, a model species, but extrapolate the potential application of these approaches to monitor the health status of wild bee populations. Biomarker-guided health measures can inform beekeeper management decisions, wild bee conservation efforts, and environmental policies. We conclude by addressing challenges to pollinator health from a One Health perspective that emphasizes the interplay between environmental quality and human, animal, and bee health.
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Affiliation(s)
- Margarita M López-Uribe
- Department of Entomology, Center for Pollinator Research, Pennsylvania State University, University Park, Pennsylvania 16802, USA;
| | - Vincent A Ricigliano
- Honey Bee Breeding, Genetics and Physiology Research, USDA-ARS, Baton Rouge, Louisiana 70820, USA; ,
| | - Michael Simone-Finstrom
- Honey Bee Breeding, Genetics and Physiology Research, USDA-ARS, Baton Rouge, Louisiana 70820, USA; ,
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Voulgari‐Kokota A, Ankenbrand MJ, Grimmer G, Steffan‐Dewenter I, Keller A. Linking pollen foraging of megachilid bees to their nest bacterial microbiota. Ecol Evol 2019; 9:10788-10800. [PMID: 31624582 PMCID: PMC6787775 DOI: 10.1002/ece3.5599] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 07/25/2019] [Accepted: 07/28/2019] [Indexed: 12/17/2022] Open
Abstract
Solitary bees build their nests by modifying the interior of natural cavities, and they provision them with food by importing collected pollen. As a result, the microbiota of the solitary bee nests may be highly dependent on introduced materials. In order to investigate how the collected pollen is associated with the nest microbiota, we used metabarcoding of the ITS2 rDNA and the 16S rDNA to simultaneously characterize the pollen composition and the bacterial communities of 100 solitary bee nest chambers belonging to seven megachilid species. We found a weak correlation between bacterial and pollen alpha diversity and significant associations between the composition of pollen and that of the nest microbiota, contributing to the understanding of the link between foraging and bacteria acquisition for solitary bees. Since solitary bees cannot establish bacterial transmission routes through eusociality, this link could be essential for obtaining bacterial symbionts for this group of valuable pollinators. OPEN RESEARCH BADGES This article has earned an Open Data Badge for making publicly available the digitally-shareable data necessary to reproduce the reported results. The data is available at https://www.ebi.ac.uk/ena/data/view/PRJEB27223, https://www.ebi.ac.uk/ena/data/view/PRJEB31610, and https://doi.org/10.5061/dryad.qk36k8q.
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Affiliation(s)
- Anna Voulgari‐Kokota
- Department of BioinformaticsBiocenterUniversity of WuerzburgWuerzburgGermany
- Center for Computational and Theoretical BiologyUniversity of WuerzburgWuerzburgGermany
| | - Markus J. Ankenbrand
- Department of BioinformaticsBiocenterUniversity of WuerzburgWuerzburgGermany
- Center for Computational and Theoretical BiologyUniversity of WuerzburgWuerzburgGermany
| | - Gudrun Grimmer
- Department of Animal Ecology and Tropical BiologyBiocenterUniversity of WuerzburgWuerzburgGermany
| | - Ingolf Steffan‐Dewenter
- Department of Animal Ecology and Tropical BiologyBiocenterUniversity of WuerzburgWuerzburgGermany
| | - Alexander Keller
- Department of BioinformaticsBiocenterUniversity of WuerzburgWuerzburgGermany
- Center for Computational and Theoretical BiologyUniversity of WuerzburgWuerzburgGermany
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30
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Voulgari-Kokota A, McFrederick QS, Steffan-Dewenter I, Keller A. Drivers, Diversity, and Functions of the Solitary-Bee Microbiota. Trends Microbiol 2019; 27:1034-1044. [PMID: 31451346 DOI: 10.1016/j.tim.2019.07.011] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 07/12/2019] [Accepted: 07/29/2019] [Indexed: 12/31/2022]
Abstract
Accumulating reports of global bee declines have drawn much attention to the bee microbiota and its importance. Most research has focused on social bees, while solitary species have received scant attention despite their enormous biodiversity, ecological importance, and agroeconomic value. We review insights from several recent studies on diversity, function, and drivers of the solitary-bee microbiota, and compare these factors with those relevant to the social-bee microbiota. Despite basic similarities, the social-bee model, with host-specific core microbiota and social transmission, is not representative of the vast majority of bee species. The solitary-bee microbiota exhibits greater variability and biodiversity, with a strong impact of environmental acquisition routes. Our synthesis identifies outstanding questions that will build understanding of these interactions, responses to environmental threats, and consequences for health.
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Affiliation(s)
- Anna Voulgari-Kokota
- Department of Bioinformatics, University of Würzburg, Biocenter, Am Hubland, 97074 Würzburg, Germany; Center for Computational and Theoretical Biology, University of Würzburg, Hubland Nord, Emil-Fischer Straße, 97074 Würzburg, Germany
| | - Quinn S McFrederick
- Department of Entomology, University of California, 900 University Ave, Riverside, CA 92521, USA
| | - Ingolf Steffan-Dewenter
- Department of Animal Ecology, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Alexander Keller
- Department of Bioinformatics, University of Würzburg, Biocenter, Am Hubland, 97074 Würzburg, Germany; Center for Computational and Theoretical Biology, University of Würzburg, Hubland Nord, Emil-Fischer Straße, 97074 Würzburg, Germany.
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